This invention relates generally to torpedo tubes for surface ships, and more particularly to an improved torpedo tube breech therefor and a method for launching torpedoes.
The vast majority of surface ships worldwide utilize substantially the same mechanism and method for launching lightweight vehicles, such as torpedoes, from a tube. This technology was first developed in the 1950""s, and has been utilized virtually unchanged since that time.
A conventional tube used for launching a lightweight vehicle, such as a torpedo, from a surface ship is schematically illustrated in FIGS. 1 and 2. In existing systems, the torpedoes are carried in a tube 10 disposed on the surface of the ship. Tube 10 is generally cylindrical in shape, and includes a discharge end 12 having a closure 16 and a breech end 14. A torpedo 18 with fins 13 is manually loaded into tube 10 through discharge end 12, upon opening of closure 16. Torpedo 18 resides in closely spaced relation with ridges or lands 15 on the side walls of tube 10. Ridges 15 are raised areas on the interior surface of the tube 10 which extend parallel to the long axis of the tube. Ridges 15 are designed not only to guide the fins 13 of the torpedo 18 but also to allow the body of the torpedo to fit snugly within the tube while allowing free passage of the fins 13. Ridges 15 also contribute to a pressure buildup upon launch, as they restrict the space within which the gas may escape in a forward direction.
Breech end 14 includes breech 20, and a weapons securing mechanism 24 for retaining the torpedo 18 within tube 10 during storage. Breech 20 is affixed to tube 10 by locking ring assembly 115, which comprises an interrupted screw mechanism. Rotation of locking ring assembly 115 allows opening of breech 20 and loading of a vehicle, such as a torpedo 18, into the breech end 14. Breech 20 includes a flask 22 and a control mechanism 26 responsive to a firing command for releasing the torpedo and expelling it from tube 10. Flask 22 contains air under high pressure. An air port 28 couples the interior of flask 22 to control system 26. Firing valve 30 permits air from within flask 22 to escape into tube 10 to expel torpedo 18, once valve 30 is opened. Weapons securing mechanism 24 includes jaws 32 which are configured to grasp a correspondingly shaped end tip 19 of the torpedo 18. Jaws 32 retain torpedo 18 in its desired position within tube 10 under normal, non-firing conditions. Jaws 32 are disposed within cylinder 31 which is slidably mounted. Cylinder 31 holds jaws 32 in their closed position grasping tip 19. Pressurized gas passed to port 27 from air port 28 by way of control system 26 causes cylinder 31 to move away from flask 22 (to the left as shown in FIG. 2) allowing the jaws 32 to open as the outer surfaces of the jaws 32 ride along sloped surface 33 of cylinder 31. Movement of cylinder 31 toward flask 22 closes jaws 32.
Firing valve 30 includes closure 34, sliding portion 36 and spring 38. Spring 38 biases sliding portion 36 against closure 34 into a normally closed position to prevent air within flask 22 from escaping to the interior of tube 10 under normal, non-firing conditions. A lever 40 is pivotally coupled to cylinder 31 at point 41, so that when cylinder 31 moves away from flask 22, lever 40 pivots and presses sliding portion 36 toward flask 22 and against the bias of spring 38 to unseat valve 30 and to allow air to escape into tube 10.
Tube 10 also includes an electrical connection 50 which provides electrical signals and power to torpedo 18 when it is being stored within tube 10. Electrical connection 50 includes an umbilical cable 52 and a plug 54 which is normally coupled to a correspondingly shaped female receptacle (not shown) in torpedo 18. Umbilical cable 52 is coupled to a lever arm 56 which is in turn coupled to a valve 58. When pneumatically actuated by air from control system 26, valve 58 pivots lever arm 56 to retract plug 54 from torpedo 18.
In operation, closure mechanism 16 is first opened to allow the torpedo 18 to pass through discharge end 12. When a command is received by control system 26 to fire the torpedo, air is bled through port 28 from the interior of flask 22 into control system 26 via a valving mechanism (not shown). The air from port 28 is conducted to port 58 to cause pivoting of lever arm 56 and thus retraction of plug 54. The air is then conducted through port 27 to cylinder 31 of weapons securing mechanism 24 causing jaws 32 to open, and lever 40 to pivot about pivot point 41. Lever 40 depresses sliding portion 36, opening firing valve 30 and releasing the high-pressure air from within flask 22 into the interior of tube 10. This air pressure is calculated to be sufficient to expel torpedo 18 from tube 10 once jaws 32 are opened to release end tip 19.
The structure and operation of the foregoing prior art torpedo tube and launching mechanism are fully described in Technical Manual SW395-AC-MMO-010/OP3355, NSNO640-LP-002-3000 entitled Description, Operation, Maintenance, and Illustrated Parts Breakdown, Surface Vessel Torpedo Tube Mark 32 Mods 5 and 7, which is published by direction of the Commander, Naval Sea Systems Command. The latest revision of this technical manual is dated Sep. 16, 1988, and is specifically incorporated herein by reference.
This prior art system has several drawbacks. In the first place, after a torpedo is manually loaded into tube 10 through breech end 14 after opening of breech 20, breech 20 must be recharged with high-pressure air. About 1600 lbs of air pressure are required for each flask 22. Therefore, it takes about one to one and one half hours to recharge the flasks for all six tubes that are normally carried on a typical ship. In adverse weather, the time required to recharge the flask in each tube can be potentially much longer. For those ships having tubes in external location outside the skin of the ship, the charging operation is also very hazardous if it must be performed in bad weather or in the dark. Some ship classes necessitate training the tubes outboard prior to charging. This recharge time produces a lengthy delay between the firing of one round of torpedoes, and readiness to fire the next round of torpedoes. Such a delay could prove disastrous in a combat situation.
Another drawback of the existing system is that all of the flasks presently found on most ships in the fleet have corrosion problems. As a partial consequence of these corrosion problems, the flasks do not hold the air charge indefinitely. They have to be recharged regularly, typically every 12-24 hours. Therefore, combat readiness could be affected by the failure to ensure that each flask remains fully charged.
Another problem associated with existing systems is that misalignment of the breech with respect to weapons securing mechanism 24 could and has caused accidental movement of lever 40 and opening of flask 22. Such an accidental opening could cause the breech to fly off while assembling the breech, or while charging the flask. Obviously, such a condition can be quite dangerous to the crew members who are involved in manually loading the tube and charging the flasks. Serious accidents have occurred during the removal and reinstallation of the air flasks, resulting in personal injury and loss of valuable man days, not to mention loss of combat readiness.
Also, all of the pneumatics associated with each tube are exposed to the salt atmosphere, and are subject to corrosion problems requiring frequent and intensive maintenance and repair.
The foregoing drawbacks of existing vehicle launch mechanisms for surface ships are overcome by the present invention, in which the air flasks in existing breeches are replaced by gas generators, which, in a preferred embodiment, are commercially available, automotive air bag gas generator inflators, that provide the energy needed to launch a vehicle, such as a torpedo, from a tube.
In one aspect of the invention, a new breech assembly is retrofitted on the breech end of an existing tube. This new breech is constructed with a retaining device containing a plurality of gas generators which are replaceable after use. This new breech assembly is retrofitted onto the existing locking ring assembly on the breech end of the tube. The retaining device provides adequate support for the gas generators to retain them in place during activation and allows rapid replacement of the gas generators after use.
In another aspect of the invention, a plurality of gas generators are employed and are activated sequentially with a predetermined time delay. This predetermined time delay produces a pressure wave of predetermined and predictable characteristics which expels the vehicle with the desired velocity and acceleration. By adjusting the number and sequence of the gas generators, the pressure wave developed by the prior art air flask can be easily replicated. This sequential firing of the gas generators preferably is electrically controlled.
In another further aspect of this invention, a cartridge is disclosed for activating the weapons securing mechanism to release the tip end of the vehicle, such as a torpedo, prior to launch. This cartridge is typically a small explosive device that can be retrofitted into the existing weapons securing mechanism pressure line to create the necessary gas pressure to open the jaws of the weapons securing mechanism.
In yet another further aspect of the invention, an improved umbilical release mechanism is disclosed for pulling the umbilical cable prior to launch. This improved umbilical release mechanism preferably is an electrically or pneumatically operated piston which pulls the existing umbilical cable in response to the launch signal.
By eliminating the need to use high-pressure air to launch a vehicle, such as a torpedo, this invention eliminates the time-consuming requirement of recharging the air flask following a launch. All that is required is replacement of the gas generators in the breech after loading of the vehicle, which can be accomplished in a relatively small amount of time. Since automotive air bag gas generators have been available for some time for automotive use, have a shelf life of 20 years, and have been demonstrated to be essentially leakproof, the risks of leaks are virtually non-existent. Thus, this invention also eliminates the need to continually recharge the flasks each 12-24 hours. Moreover, the leakage of air due to corrosion has been eliminated, and the risk of the breech flying off has also been eliminated, since high-pressure gasses are no longer used for the control mechanism.
As a consequence, the potential for injury is virtually eliminated. The tubes are always combat ready once the gas generators have been loaded, and the time required to render a particular tube firing ready after launch is substantially reduced. As a result, the ship can be maintained in a higher state of combat readiness than is possible with existing systems. Also, significantly less maintenance is required to maintain this combat readiness.
Finally, significantly, the implementation of this mechanism does not require replacement of existing tubes or changes in the method of loading or firing existing torpedoes. Rather, this improved breech mechanism can be retrofitted onto existing tubes utilizing the existing locking flange design and firing electronics. As a result, all existing hardware can still be used, including storage racks, handling equipment and launch computers. Also, most operational procedures can be maintained, or even eliminated as the reloading process is streamlined.